Device for testing steel pipe weld quality using variable frequency ultrasonic technology

Abstract

The present application relates to a device for frequency-variable ultrasonic testing of the quality of steel pipe welds, and relates to the field of ultrasonic testing technology. The device comprises a transmitting box and a receiving box, wherein the transmitting box and the receiving box are arranged on both sides of the wall of the steel pipe to be tested, and a plurality of first transmitting transducers are distributed circumferentially on the transmitting box, a second transmitting transducer is arranged in the center of the plurality of first transmitting transducers, and a power amplifier is connected below the first transmitting transducer and the second transmitting transducer; and a plurality of receiving transducers are evenly distributed on the receiving box. The present application has a function of transmitting a signal through a combination of one of the first transmitter and the second transmitter as a sound source for testing the steel pipe. After the receiving transducer receives the signal, it calculates the propagation speed of the sound wave by the wavelength and frequency. If the speed is low, there is a problem with the weld, which may be mixed with other impurities or a poor weld, and there are some bubbles. In this way, the detection is driven by different frequencies to form difference frequency and sum frequency, thereby improving the detection resolution.

Description

Technical Field

[0001] The present application relates to the field of ultrasonic testing technology, and in particular to a device for detecting the quality of steel pipe welds using variable frequency ultrasonic testing. Background Art

[0002] Steel pipes are made by bending steel plates and then welding them. In order to ensure the quality of the steel pipes, the quality of the welds needs to be tested after welding is completed.

[0003] Existing ultrasonic testing technology uses a single frequency for detection. The detection resolution of a single frequency is limited, making it difficult to cover the quality inspection of different welds, especially the quality of tiny welds, which is easy to miss. Summary of the Invention

[0004] In order to solve the above-mentioned problem of easy missed detection in single frequency detection, the present application provides a device for variable frequency ultrasonic detection of steel pipe weld quality.

[0005] This application provides a device for detecting the quality of steel pipe welds using variable frequency ultrasonic waves, which adopts the following technical solutions:

[0006] A device for frequency-converting ultrasonic testing of steel pipe weld quality, comprising a transmitting box and a receiving box, the transmitting box and the receiving box being arranged on either side of a wall of a steel pipe to be tested, the transmitting box having a plurality of first transmitting transducers distributed circumferentially thereon, a second transmitting transducer being arranged at the center of the plurality of first transmitting transducers, power amplifiers being connected below the first transmitting transducers and the second transmitting transducers, the first transmitting transducers and the second transmitting transducers being in contact with the steel pipe to be tested;

[0007] A plurality of receiving transducers are evenly distributed on the receiving box. The receiving transducers are in contact with the steel pipe to be inspected and are suitable for receiving signals from the first transmitting transducer and the second transmitting transducer after they pass through the steel pipe to be inspected.

[0008] By adopting the above technical solution, the multi-frequency power amplifier outputs different signal frequencies to drive the first transmitting transducer and the second transmitting transducer respectively. A signal is emitted through a combination of one of the first transmitter and the second transmitter as the sound source for detecting the steel pipe. After the receiving transducer receives the signal, the sound wave propagation speed is calculated by the wavelength and frequency. If the speed is low, there is a problem with the weld, which may be mixed with other impurities or a cold weld, or there may be some bubbles. Then the amplitude of the sound wave is compared. If the amplitude becomes smaller, it means that the attenuation becomes larger, and there may be a problem with the weld. In this way, the detection is driven by different frequencies to form difference frequency and sum frequency, thereby improving the detection resolution.

[0009] Optionally, the first transmitting transducer is a high-resonance frequency transmitting transducer, and the second transmitting transducer is a low-resonance frequency transmitting transducer, and the resonant frequency is between 100 kHz and 1 MHz.

[0010] By adopting the above technical solution, the advantage of the high resonant frequency transmitting transducer is its high resolution, which can detect the quality of smaller-scale welds; the advantage of the low resonant frequency transmitting transducer is its strong sound wave penetration and low attenuation, which can penetrate the steel pipe to be tested for detection.

[0011] Optionally, the transmitting box is arranged on a pan-tilt platform, and the pan-tilt platform is suitable for moving along the axial direction of the steel pipe to be inspected.

[0012] By adopting the above technical solution, the signal can be transmitted to the receiving transducer at the corresponding position through the movement of the pan-tilt head, so as to obtain the detection result, and the welds at different positions can be detected with more accurate results.

[0013] Optionally, the receiving transducers are arranged along the half-wavelength of the axial direction of the steel pipe, and adjacent different receiving transducers have opposite polarization polarities.

[0014] By adopting the above technical solution, the polarization polarity of the receiving transducer is opposite, ensuring that the receiving transducer and the transmitted signal can correspond one to one, thereby ensuring the accuracy of detection.

[0015] Optionally, the receiving transducer is connected to a preamplifier unit.

[0016] By adopting the above technical solution, the preamplifier unit amplifies the received initial signal to facilitate analysis.

[0017] Optionally, the receiving transducer is connected to a wide-gain signal receiver via a differential cable.

[0018] By adopting the above technical solution, the differential signal is output by the receiving transducer using two independent cables, which can avoid the environmental noise introduced by the traditional use of a common ground wire.

[0019] Optionally, the distance between the first transmitting transducer and the second transmitting transducer is a multiple of the wavelength of the sound wave.

[0020] In summary, this application includes at least one of the following beneficial technical effects:

[0021] 1. The multi-frequency power amplifier outputs different signal frequencies to drive the first and second transmitting transducers respectively. A signal is emitted through the combination of the first and second transmitters, serving as the sound source for detecting steel pipes. After receiving the signal, the receiving transducer calculates the sound wave propagation velocity based on the wavelength and frequency. If the velocity is low, there is a problem with the weld, possibly due to impurities, a poor weld, or bubbles. The amplitude of the sound waves is then compared. If the amplitude decreases, it indicates increased attenuation, suggesting a possible weld problem. This detection method utilizes different frequency drives to form difference and sum frequencies, improving detection resolution.

[0022] 2. The advantage of high resonant frequency transmitting transducer is high resolution, which can detect the quality of smaller-scale welds; the advantage of low resonant frequency transmitting transducer is strong sound wave penetration and low attenuation, which can penetrate the steel pipe to be tested;

[0023] 3. Differential signaling is when the receiving transducer uses two independent cables to output the signal, which can avoid the environmental noise introduced by the traditional use of a common ground wire. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural diagram of an embodiment of the present application;

[0025] Figure 2 This is a schematic diagram of a launch box in an embodiment of the present application;

[0026] Figure 3 This is a schematic diagram of a receiving box in an embodiment of the present application.

[0027] Explanation of the accompanying drawings: 1. First transmitting transducer; 2. Second transmitting transducer; 3. Receiving transducer; 4. Transmitting box; 5. Receiving box; 6. Steel pipe to be tested. DETAILED DESCRIPTION

[0028] The following is combined with Figure 1 This application is described in further detail.

[0029] The embodiment of the present application discloses a device for detecting the quality of steel pipe welds by variable frequency ultrasonic testing. Figure 1 The device for frequency conversion ultrasonic testing of steel pipe weld quality includes a transmitting box 4 and a receiving box 5. The transmitting box 4 and the receiving box are arranged on both sides of the wall of the steel pipe 6 to be tested. The transmitting box 4 is circumferentially distributed with a plurality of first transmitting transducers 1. A second transmitting transducer 2 is arranged at the center of the plurality of first transmitting transducers 1. A power amplifier is connected below the first transmitting transducer 1 and the second transmitting transducer 2. The multi-frequency power amplifier outputs different signal frequencies to drive the first transmitting transducer 1 and the second transmitting transducer 2 respectively. The two transmitting transducers are coupled to produce Generate sum frequency and difference frequency signals as the sound source for detecting steel pipe welds; the first transmitting transducer 1 and the second transmitting transducer 2 are fitted with the steel pipe 6 to be detected, and a number of receiving transducers 3 are evenly distributed on the receiving box 5. The receiving transducers 3 are fitted with the steel pipe 6 to be detected, and the receiving transducers 3 are suitable for receiving the signals of the first transmitting transducer 1 and the second transmitting transducer 2 after passing through the steel pipe 6 to be detected. The receiving transducer 3 can adjust the gain of the signal and the amplitude of the received signal to meet the signal analysis requirements after different sound waves propagate through the steel pipe 6 to be detected.

[0030] Specifically, the multi-frequency power amplifier can adjust the transmission energy of the first transmitting transducer and the second transmitting transducer 2 by adjusting the duty cycle of the signal to meet the detection requirements of different steel pipes.

[0031] The multi-frequency power amplifier outputs different signal frequencies to drive the first transmitting transducer 1 and the second transmitting transducer 2 respectively. A signal is emitted through a combination of one of the first transmitter and the second transmitter as the sound source for detecting the steel pipe. After the receiving transducer 3 receives the signal, the sound wave propagation velocity is calculated by the wavelength and frequency according to the formula wavelength = sound wave propagation velocity divided by frequency. Since the wavelength is inversely proportional to the frequency, and the frequency is proportional to the resolution, when the velocity is low, there is a problem with the weld, which may be mixed with other impurities or a cold weld, and there are some bubbles. Then, the amplitude of the sound wave is compared. If the amplitude becomes smaller, it means that the attenuation becomes larger, and there may be a problem with the weld. In this way, the detection is driven by different frequencies to form difference frequency and sum frequency, thereby improving the detection resolution.

[0032] Among them, in order to realize the generation of difference frequency and sum frequency by the first transmitting transducer 1 and the second transmitting transducer 2, the first transmitting transducer 1 is a high resonant frequency transmitting transducer, and the second transmitting transducer 2 is a low resonant frequency transmitting transducer. The distance between the first transmitting transducer 1 and the second transmitting transducer 2 is a multiple of the wavelength of the sound wave, and the resonant frequency is between 100kHz and 1MHz. For example, the second transmitting transducer 2 is 8kHz and the first transmitting transducer 1 is 10k, then 4k and 18k signals can be generated. The advantage of the high resonant frequency transmitting transducer is high resolution, which can detect the quality of smaller-scale welds; the advantage of the low resonant frequency transmitting transducer is strong sound wave penetration and low attenuation, which can penetrate the steel pipe to be tested for detection.

[0033] Specifically, the transmitting box 4 is set on a pan-tilt platform, which is suitable for moving along the axial direction of the steel pipe 6 to be tested, and can transmit the signal to the receiving transducer 3 at the corresponding position, thereby obtaining the detection result. It can detect welds at different positions and the result is more accurate.

[0034] The receiving transducers 3 are arranged along the half-wavelength of the axial direction of the steel pipe, and the polarization polarities of adjacent and different receiving transducers 3 are opposite, ensuring a one-to-one correspondence between the receiving transducers and the transmitted signals, thereby ensuring the accuracy of the detection.

[0035] In one embodiment, the receiving transducer 3 is connected to a preamplifier unit, which amplifies the received initial signal for easy analysis, and the receiving transducer 3 is connected to a wide-gain signal receiver via a differential cable. The two independent differential cables transmit differential signals, and the differential signals are transmitted from the receiving transducer 3 to the wide-gain signal receiver, which can avoid the environmental noise introduced by the traditional use of a common ground wire.

[0036] The above are all preferred embodiments of the present application, and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A device for detecting the quality of steel pipe welds using variable frequency ultrasonic waves, characterized in that: The invention comprises a transmitting box (4) and a receiving box (5), wherein the transmitting box (4) and the receiving box (5) are arranged on both sides of the wall of the steel pipe (6) to be detected, a plurality of first transmitting transducers (1) are distributed circumferentially on the transmitting box (4), a second transmitting transducer (2) is arranged at the center of the plurality of first transmitting transducers (1), a power amplifier is connected below the first transmitting transducer (1) and the second transmitting transducer (2), and the first transmitting transducer (1) and the second transmitting transducer (2) are in contact with the steel pipe (6) to be detected; A plurality of receiving transducers (3) are evenly distributed on a receiving box (5), wherein the receiving transducers (3) are in contact with the steel pipe (6) to be inspected, and the receiving transducers (3) are suitable for receiving signals from the first transmitting transducer (1) and the second transmitting transducer (2) after the signals pass through the steel pipe (6) to be inspected; the first transmitting transducer (1) is a high-resonance frequency transmitting transducer with a resonant frequency of 100 kHz to 1 MHz, and the second transmitting transducer (2) is a low-resonance frequency transmitting transducer; The receiving transducers (3) are arranged along the axial direction of the steel pipe, and adjacent different receiving transducers (3) have opposite polarization polarities; The distance between the first transmitting transducer (1) and the second transmitting transducer (2) is a multiple of the wavelength of the sound wave.

2. The device for detecting the quality of steel pipe welds using variable frequency ultrasonic testing according to claim 1, characterized in that: The transmitting box (4) is arranged on a platform, and the platform is suitable for moving along the axial direction of the steel pipe (6) to be detected.

3. The device for detecting the quality of steel pipe welds using variable frequency ultrasonic testing according to claim 1, characterized in that: The receiving transducer (3) is connected to a preamplifier unit.

4. The device for detecting the quality of steel pipe welds using variable frequency ultrasonic testing according to claim 3, characterized in that: The receiving transducer (3) is connected to a wide-gain signal receiver via a differential cable.

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